The present invention relates to a liquid crystal display device and, more particularly, to a liquid crystal display device with a sealant layer provided between a pair of transparent substrates of which construction prevents a liquid crystal material from penetrating into the peripheral space outside the sealant layer during the introduction of the liquid crystal material.
According to conventional manner, a liquid crystal display panel comprising a liquid crystal material introduced between transparent substrates is constructed as follows:
A frame-like sealant layer is provided on one transparent substrate so as to be spaced apart by a certain distance off the peripheral edge except the part of a liquid crystal introduction inlet. The transparent substrate is bonded to a counterpart transparent substrate by the sealant layer. The resultant structure is evacuated, and then placed on liquid crystal boat 6 filled with liquid crystal material 8 with liquid crystal introduction inlet 4 immersed in the liquid crystal material 8 thereby the liquid crystal material 8 is introduced between the two substrates 1a and 1b by suction, as shown in FIGS. 5 and 6. Here, FIG. 5 is an explanatory view for exemplifying a manner of introducing a liquid crystal material into a conventional liquid crystal display panel, and FIG. 6 is a sectional view taken along line I--I of FIG. 5.
However, liquid crystal material 8, as shown in FIG. 6 upon introduction thereof, penetrates even into circumference (peripheral space) 7 outside the sealant layer 2 by capillary action. For this reason, a cleaning operation is required to remove the liquid crystal material left in that space 7 after the introduction. Since the space 7 is very narrow, or as narrow as 5 to 10 .mu.m, the cleaning operation involves difficulty. Moreover, since the use of flon is not permitted recently, the cleaning operation is more difficult. If the liquid crystal material is left in an electrode terminal portion due to incomplete cleaning, the electrode terminal tends to be broken, which leads to a degradation of the reliability of the liquid crystal display device.
In an attempt to prevent the liquid crystal material from elevating to the peripheral space 7, there is disclosed in Japanese Unexamined Patent Publication No. 180520/1989 a liquid crystal display device provided with liquid-crystal-elevation stoppers 11a and 11b which are, respectively, formed of protrusions of sealant layer 2 in the shape in section and located on the opposite sides of liquid crystal introduction inlet 4 as shown in FIG. 7.
The provision of such liquid-crystal-elevation stoppers 11a and 11b, however, cannot completely prevent the liquid crystal material from elevating to the peripheral space defined between the transparent substrates. The liquid crystal material elevates into about 30% of panels with such spaces, resulting in a problem of making defective products. In detail, usually a liquid crystal display panel is produced by printing a plurality of sealant layers and the like on a large glass plate and then cutting the large glass at around each of the sealant layers so as to be cut between adjacent any two sealant layers having a frame-like shape. Thus individual panels are obtained. Hence, even if protrusions of the sealant layer are formed to serve as stoppers, they cannot be made to squeeze out of the peripheral edge of the transparent substrates. In addition, minute unevenness is produced on the surface of the sealant layer to cause the liquid crystal material to elevate onto the surface by capillary action. Thus, the stoppers cannot achieve their purpose.